Compressor for refrigerating apparatus



Dec. 29, 1942.A E. F. HUBACK'ER 2,306,608

COMPRESSOR FOR REFRIGERATING APPARATUS Filed Feb. 5, 1940 2 Sheets-Sheet l Dc.29,1942. E.F.HUBAKER 2,306,608

COMPRESSOR FOR REFRIGERATING APPARATUS Filed Feb. 5, 1940 2 Sheets-Shea?, 2

[NVENTOR Patented Dec. 29, 1942 COMPRESSOR FOR REFRIGERATING APPARATUS Earl F. Hubacker, Highland Park, Mich., assignor to Borg-Warner Corporation, Chicago, Ill., a corporation o f Illinois Application February 5, 1940, Serial No. 317,223

2 claims. (ci. 23o- 207) This invention relates to the art of refrigeration and has particular reference to a new and improved form of reirigerating system and motor compressor unit for use therein.

A principal object of the invention is to provide an improved refrigeration system of the compressor-condenser-expander type, wherein a motor compressor unit is arranged in a sealed casing which forms a part of the low pressure side of the system.

Another object of the invention is to provide a .new and improved form oi motor compressor unit for use in refrigerating systems. V

Another object of the invention is to provide a novel form of motor compressor' construction which is better adapted for use in a sealed unit.

Another object of the invention is to provide a novel form of rotary compressor construction which is arranged in a bath of oil subjected to the suction pressure of the compressor, with provisions for supplying oil under the discharge pressure of the compressor to certain of the moving parts thereof :for sealing and lubrication DllrDOSeS- Other objects and advantages of the invention will be apparent from a consideration of the following specification taken in conjunction with the accompanying drawings,'of which there are two sheets. and wherein:

Fig. 1 is an elevational view of a refrigerator having a refrigerating system which embodies my invention;

Fig. 2 is a vertical sectional view, with parts broken away, of the motor compressor part of the system;

Fig. 3 is a sectional view through the compressor of the motor compressor unit, taken in a plane along the line 3-3 of Fig. 2, looking in the direction of the arrows;

Fig. 4 is a horizontal section of the compressor, taken in a plane along the line 4-4 of Fig. 2,- looking in the direction of the arrows; and

Fig. 5 is a bottom plan view of the compressor, taken generally in a plane along the line 5-5 of Fig. 2.

Referring now to Fig. 1, there is illustrated a part of a .refrigerator which includes a heat insulated provision compartment I0 having a heat absorbing element I2 of a refrigerating system arranged therein. Said system further includes a motor compressor unit I4 and a condenser I6 operatively connected with the heat absorbing element or evaporator I2. Gaseous refrigerant is returned from the evaporator I2 to the motor compressor unit I4 by the suction line I8, and 55 from the motor compressor unit, high pressure refrigerant vapor is conducted by a conduit 20 to one end of the condenser. From the other end of the condenser, liquid refrigerant is supplied by liquid line 22 to the evaporator under the control of a suitable regulating means. In the system herein illustrated, the casing of the motoi compressor unit I4 forms a part of the low pressure side of the system, as will be further eX- plained herein.

The construction of the motor compressor unit is more particularly illustrated in Figs. 2, 3, 4 and 5 and in general comprises a sealed casing 24 having arranged therein an electric motor 2B and a rotary compressor 28. The casing 24 may, as illustrated,` comprise a deep-drawn shell 25 closed by a cap 2l, the edges of the cap l21 and the shell 25 being flanged outwardly and hermetically connected such as by Welding. The interior of the casing 24 comprises a low pressure refrigerant gas and lubricant reservoir, the lubricant collecting in the bottom of the reservoir to approximately the level of the joint between the shell 25 and casing 2l.

A frame, comprising a sleeve 30 and a bearing plate 32, is supported within'the casing 24 and above the bottom thereof, the sleeve preferably being pressed into the shell 25 of the casing 24, as illustrated. The periphery of the bearing plate 32 and the lower end of the sleeve 30 preferably are provided with complementary interfitting aligning surfaces, so that the axis of the bearing 34 coincides with the axis of the sleeve 30 and the bearing plate 32 may be removably assembled to the sleeve 30 by means of a plurality of bolts 36, the threaded portions of which are received in nuts 38 carried by the sleeve 30. Bearing plate 32 is circular and includes an axially extending projection which forms a bearing 34 for a shaft 31. The bearing' plate 32 is provided with several apertures 40 so as to permit lubricant to drain into the lower part of the casing 24. The motor 26 includes a stator 42, which is pressiitted in the sleeve 30, and a rotor 44 which is `arranged inside of the stator and aixed to the upper end of shaft 3l for driving the same. Current is supplied to the stator 42, for energizing the same, by means of several insulated conductors 46, which make a sealed joint between the current conducting wire and the casing 24.

The bearing plate 32 is provided with a projection'on. the under side thereof, which forms an end plate 48 of a rotary compressor and which further includes a cylinder 5U, a rotor 52, a divider 54, an eccentric 56, a bottom end plate 58. and a valve plate 60. The end plates 48 and 58 and the cylinder 50 are rigidly assembled together in such a way as to form a closed cylindrical chamber or pumping space and in which the rotor 52 is arranged for oscillation. The rotor 52 is freely journaled on the eccentric 56 and, it will be observed, is of less diameter than the pumping chamber 62 in which itis arranged. The rotor 52 is of such size, relative to the cylinder 50, that there is a small working clearance between the horizontal faces of the rotor and the adjacent horizontal faces of the end plates 48 and 58. Also, the diameter of the rotor 52 is such that there is a slight clearance between the periphery of the rotor 52 and the adjacent cylindrical wall of the pumping chamber 62 at that point where the rotor 52 divides one side of the charged by the compressor to onefend of the condenser.

One end of a duct 88 formed in the end plate 58 and valve plate 60 communicates with the bottom of the chamber 80, and the other end of such duct 88 communicates with a groove 80 formed in the shape of an arc and in the upper surface of the end plate 58 and `directly opposite pumping chamber 62 from the other side thereof. as illustrated in Fig. 3, and this clearance is' maintained as the rotor gyrates or moves around the pumping chamber 62 in a counter-clockwise direction, looking at Fig. 3.

'I'he divider 54 is arranged for reciprocation within a slot formed in the cylinder 50 and is biased into engagement with the peripheryk of the rotor, as illustrated in Fig. 3, so as to separate the suction gas from the discharge gas in the pumping chamber 62. The divider 54, it will be observed, comprises a major segment of a cylinder and includes a fiat surface which slides on a iiat surface of the slot in which the divider 54 reciprocates. The divider 54 preferably is of the same vertical dimension as the rotor 52, so that the divider 54 will form a moving seal between the periphery of the rotor 52, and the walls of the pumping chamber 62. `The slot in which the divider or blade 54 operates is of such size that thepressure on the dicharge side of the chamber 62 is communicated to the space at the back of the slot behind the divider, so that the difference in pressure between the intake and discharge sides of the compressor will function to aid in causing the divider 54 to follow the rotor 52 upon oscillation thereof.

The pumping chamber is provided with an intake port at 64 and with a valve controlled discharge port at 66. The divider 54 is guided in its movement by a pin 68 which is slidable in a bore formed in the wall of the cylinder, one

end of the pin being seated in a cavity in the rear side of the divider or blade 54 and the other end of the pin, which extends outside of the cylinder 50, being provided with a cap upon which is seated one end of a spring 12, the other end of the spring being seated in the end of a cap 14 which is screw threaded on to a pro-v jection 16 formed on the external wall of the cylinder 50. Spring 12, through pin 68, acts to hold the divider 54 in contact with the periphery of the rotor 52. The intake port 64 is connected by a tube 18 to the upper part of the casing 24, the upper end of the tube 18 being open. The discharge port 66, which is formed in the end plate 58, opens into a chamber 80 in which the valve 82, which controls the discharge port, is arranged. The valve 82 is a ap or check valve and is anchored at one end thereof by means of screws 84 to the under side of end plate 58. The discharge tube or conduit 20 has one end thereof seated in anl opening 86 in the valve plate 60 which communicates with the chamber 80, and such discharge tube 20 extends through a sealed opening in the casing 24 and serves to conduct the compressed gas disthe rotor 52. Another duct 92, formed in the valve plate 60, end plate 58 and cylinder 50 (Fig. 3) at one end thereof, communicates with the lower part of chamber 80 and at the other end thereof communicates with the space enclosed by the cap 14. The space within the cap 1,4 is sealed from the space exteriorly thereof by the threaded connection between the side of the cap 14 and the projection 16 formed on the external wall ofthe cylinder 50. The chamber 80 serves as an oil trap, and from the bottom of the chamber 89 oil under the discharge pressure of the compressor is iorcedvthrough ducts 88 and 82 to the groove 90 and to the space enclosed by the cap 14. The oil supplied tothe groove 90 under the discharge 'pressure of the compressor serves to seal the clearance between the end of the rotor 52 and the end plate 58, while the oil supplied by the duct 92 to the space within the cap 14 is forced past the pin 68-and into the back of the slot in which the divider'reciprocates, for lubrication and sealing purposes, particularly for thepurpose of supplying lubricant to the clearance between the ends of the divider 54 and the cylinder end plates 48 and 58 and to the at surface upon which the divider 54 slides.

The bottom end of the eccentric 56 slides upon the upper surface ofv the end plate 58 which thereby forms a thrust bearing for the shaft 81. The end plate 58 may be provided with a groove 94 at the center thereof and as illustrated in Fig. 4. This groove 84 is supplied with oil, as will be explained hereinafter. The end plate I8 and valve plate 60 are provided with openings coincidental with the axis of the shaft '81 and through which openings. extends a small diametered screw |00 formingan extension of the shaft 31. The screw |00, on the end thereof which extends below the valve plate 60, is provided with an impeller |02 which rotates within a chamber formed by a stamping |04 secured to the under side of the valve plate 60. The stamping |04 has a central opening |06 through which lubricant from the bottom of the casing 24 is drawn by rotation oi the impeller |02, which forces lubricant through a conduit |08 (formed in the valve plate 6l, end plate 58, cylinder 50 and end plate 48) into a reservoir ||0 formed by an annular ring ||2 affixed to the upper side ofthe bearing plate 32 and around the bearing 34.

From the reservoir ||0 oil is supplied by means of a plurality ofy ducts such as ||4 to a chamber ||6 formed between the rotor 52 and the end plate 48 and around the lower end of the shaft 31. From the chamber ||6 oil is fed upwardly to the surfaces of the bearing by a spiral groove' rotor 52 and thence downwardly into the cham-i' ber in whichthe impeller |02 is located.

Thus, it will be seen that lubricant is supplied to the shaft 31 and to the eccentric 55 for lubricating the same. supplied to the chamber I I 6 and to the groove 94 functions to seal the clearance between the rotor 52 and the end platesl 48 and 58. During the operation ofthe compressor, some lubricant will be drawn through the `clearance between the 10 sides of the rotor 52 and the end plates into the chamber 62 on the intake side thereof. Such lubricant, togetherwith the lubricant entrained\ in the suction gas supplied by the conduit 'I8 and the lubricant which is forced by the high pressure past'fthe divider 54, will be swept around the chamber 62 by gyration ofthe rotor 52 and serve to seal the clearance between the rotor 52 andl the internal wall of the cylinder 50 as well as to seal the clearance between the ends of the divider 54 and the adjacent end plates. Most of l.

the lubricant which enters thepumping chamber 62 will bedischarged along with the comdischarge valve will remain open until the rotor has completed itsastroke, which occurs when the high point on the rotor has reachedI the divider 54. As the pressure infthe pumping chamber reaches its maximum, just before and during the time that the discharge valveis open, thepressure drop across the rotor 52, viz., between/:that part of the pumping chamber 62 in communication with .the discharge port Yand the hollow interior of the rotor, will be the greatest. However, the groove' 90 extends acrossthe end plate 45 between such highl pressure discharge space and the interior of 'the rotor and serves to seal vmorell effectively the clearance ybetween the rotor 52 and the bottomend plate "58m i The oil which is forced upwardly along the shaft 31 by the grooveI I8 escapes at the upperl end of the bearing 34 and flows downwardly on to the oil slinger'l22 which discharges the oil L(against thebaffle |241 said baille serving to deflect I, the oil downwardly and out offcontact with the lower end 'of the stator 42. The oil collects reither in the reservoir ||0 or by overflow returns through the openings 40 into the reservoir' in the/ bottom of the casingy 24." The pump |02 supplies oil to the reservoir |,III at a rate which is faster man .that at which the ou win be drawn there- 6 yfrom through the ducts ||4, and thefexcess oil will; overflow and'return to the reservoir ,in the bottom of the casing `24. Due to the circulation of oil over the compressor,` the dissipation of heat from the same will be expedited.

It is contemplated that sulphur,y dioxide may be used as a refrigerant in the system, but due to the fact that the interior of the casing 24 is ata low pressure, the refrigerant in the casing 24 will be in a gaseous form except for the very` slight amount which might/ be absorbed in the oil. However, during the operation of the compressor, the heat of the same, together with the,

low pressure prevailing within the casing 24, will` Also, the'lubricant which is 5 the 30' I serve to keep the lubricant reasonably free of refrigerant. In this 'manner the lubricant which is supplied to the working parts of the compressor will be substantially free of refrigerant.

Refrigerant gas is supplied to the interior of the casing by suction line I8 which communi cates with the vapor space in the evaporator I2. The discharge conduit 20, as previously explained, conducts high pressure gas from the compressor to one end of the condenser I6. In the condenser, which may be an air-cooled finned tube, the refrigerant vapor, due to the dissipation of heat, will be converted into a liquid.

From the first pass of the condenser, liquid refrigerant ymay be conducted by conduit 2| to an annular jacket |26 formed between the'sleeve 30 and a bulged-out portion of the casing 24.- Passing through the jacket, the liquid refrigerant under high pressure would absorb heat from the motor windings 26. From the jacket |26 refrigerant is conducted by conduit 2'3 to the second\pass of the condenser, and from the bottom of the second pass of the condenser, liquid refrigerantis conducted by a conduit I1 to a high 5 side float |9 which meters the flow of liquid refrigerant from the high side of the system to theevaporator which is on the low side of the tube I8 and the liquid refrigerant in the tube '22,/

While the invention has been described with some detail, it is to be understood that the description is for the purpose of illustration only.`

and is not definitive of the limits of the inventive idea. The right is reserved to make such changes in the details vof construction and arrangement 'of parts as will ,fall within the purview of the attached claims.

I claim: 1. In a refrigerating systemv having a high comprising a part of the low pressure side and forming alow pressure gas and lubricant reservoir, a rotary compressor in saidl casing submerged in the lubricant, said compressor includsaid slot and engageable with'said rotor, said cylinder having an intake port on one side of said divider and means defining a pressure responsive discharge valveiassembly on the other side of said'divider, means defining a lubricant trap in the Wall of said housing in direct communication with said discharge valve assembly, and passage defining means for delivering lubricant from the lower portion of sai'd trap under the discharge pressure of said compressor into lubricating contact with the rear of said divider.

' 2. In` a refrigerating system havinga high pressure side and a low pressure side, a casing comprising a part of the low pressure side and forming a lowA pressure gas and lubricant reservoir, a rotary compressor in said vcasing and including means defining a housing formed therein with a cylinder, a driving shaft having an eccentric within the cylinder, a hollow rotor freely journaled on said eccentric, means for supplypressure side and a low pressure side, a casing ving'means defining a housing formed with a cylinder therein, a driving shaft having an eccentric within the cylinder, a hollow rotor freely journaled on said eccentric, said cylinder having a' slot in the wall thereof, a divider reciprocable in ing lubricant from said reservoir to the` interior of said hollow rotor at both ends thereof, said cylinder having a slot in the wall thereof, a dividery reciprocable in said slot and engageable with the periphery of said rotor, said cylinder having an intake port on one side of said divider and means defining a. pressure responsive discharge valve on the other side of said divider, means dening a. conduit connected to said discharge valve and leading through the wall of said 10 casing to the high pressure side of said system,

Vsaid last named means including an oil trap formed in the wall of said housing directly adjacent said discharge valve, and lubricant conveying means including a radial groove formed in the cylinder end wall at one end of the rotor for supplying lubricant from said trap to said rotor under the discharge pressure of said compressor during the operation thereof.

EARL F. HUBACKER. 

